Subgrading attachment for power graders



March 15, 1932 7 z T. DARRow 1,849,754

SUBGRADING ATTACHMENT FOR POWER GRADERS Filed Aug. 26, 1930 2 Sheets-Sheet 2 [N VENTOR BY r I A ORINEY Patented Mar. 15, 1932 UNITED STATES ZAGHERY T. DARROW, OF CANANDAIGUA, NEW YORK SUBGRADING ATTACHMENT FOR POWER GRADERS Application filed August 26, 1930. Serial No. 477,928.

This invention relates to power grading apparatus for grading roads and has for its ob.- ject to provide this type of apparatus with an attachment for independently and uniforinly supporting the grading blade where by the apparatus may be used for sub-grading road beds in the construction of concrete roads.

Another object of this invention is to provide a raking attachment in combination with the grading blade which cooperates therewith to rake the surface of the road bed ahead of the grading blade in order to loosen the surface of the road bed and rake out the larger stones and thus prepare the surface to permit the grading blade to produce a perfect grade in the road bed.

Another object of this invention is to provide both the grading blade and the raking attachment with suitable adjusting and operating means whereby the grading blade and the raking attachment may be set in any desired position and manipulated to subgrade to any desired depth.

Other objects and attendant advantages will become more readily apparent from the detailed description of one embodiment of the invention which follows, reference being had to the accompanying drawings in which Figure l is a diagrammatic side elevation of a power driven grading apparatus to which the blade and rake attachments have been added, the grading apparatus being shown in position for the subgrading operation of the road bed between the forms which provide the mould into which the concrete is poured to form the road proper.

Figure 2 is a cross section of the road bed and the forms or rails anchored at each side thereof, the blade of the grader being shown suspended between the forms in contact with the surface of the road bed by means of the supporting attachments thereof to produce the desired subgrade for the surface of the road bed, the raking attachment being shown in front of the grader blade with the teeth thereof digging into the surface of the road bed to a depth that insures loosening of the surface and the raking out of the larger stones ahead of the graderblade.

Figure 3 is a detail perspective view of one end of the grader blade and the supporting attachment thereof.

Figure a is an enlar ed detail perspective view of one of the attachments for supporting the ends of the grading blade.

In the several figures of the drawings like reference numerals indicate like parts.

The grading blade and raking attachments for a power grading apparatus forming the subject matter of my present invention make possible the use of this type of apparatus for subgrading road beds in the construction of concrete roads. At the present time subgrading is done mostly by hand labor and this method is both slow and expensive because it requires a number of laborers for this work. With my present invention this same work is done very much faster and better and with the aid of an apparatus with which practically every contractor is now equipped.

Such a power grading apparatus is diagrammatically illustrated in Figure l of the drawings and comprises a frame 1 which is supported at the rear by suitable wheels or V crawlers 2 and at the front by the wheels 3. The front wheels can be steered by a suitable steering mechanism operated by the steering rod 4 and the steering wheel 5.

The grading operation is performed by the blade 6 which extends transversely of the grader frame and is suspended from an auxiliary frame 7 which can be raised or lowered by means of a suitable mechanism operated by the hand wheel 8. The blade is also mounted on this auxiliary frame so that it can be turned into any angular position with relation to the sides of the road bed. The grader blade proper is mounted on a pair of brackets 6A and 6B which extend down the rear of the blade and are pivoted near the bottom of it at 9 and 10 to permit the tilting of the blade into any desired angle. At the top the grader blade carries smafll rearwardly projecting brackets 11 and 12 which engage the pair of brackets 6A and 6B and are bolted thereto to hold the top of the blade in the desired angular position.

So far I have described a conventional type of power grader now in universal use by contractors for road grading work. This mechanism is supplemented by my invention to also make possible with this type of apparatus the subgrading of a road bed prior to having the concrete poured into it. This invention comprises means whereby the grader blade is adjustably supported at each end and consists of a pair of arms 13 and 14k provided at each end of the grading blade 6 which in turn are supported by the guiding and supporting shoes 15 and 16. These supporting and guiding shoes are adapted to rest on top of the forms or rails 17 and 18 between which the road bed is formed. These rails or forms are located, leveled and anchored so as to project a predetermined uniform distance from the ground so that the top surface of the concrete, when poured between these forms, can be properly gauged and finished with relation thereto.

Each of the supporting and guiding shoes comprise a base plate 19 which is preferably slightly curved upwardly at each end thereof. The base plate is cut out at 20 and 21 and at each side of the cut out portion are provided suitable bearing blocks between which a pair of rollers 22 and 523 are mounted to rotate in such a manner that part of the rollers projectthru the cut out portions of the base plate and support the base plate at a slight elevation above the top of the form or rail sufiiciently to secure a free rolling contact for the rollers on the rails. This rolling support of the guiding and supporting shoes on the forms or rails is provided to reduce the friction between the r ils and the supporting shoes to a minimum.

In the middle of each of the guiding and supporting shoes is provided the upright 2% which has a flange or base Q-lA. This base is pivoted on the shoe by means of the pivot stud 25 which passes thru the base and is threaded into the shoe. A locking pin 26 is also provided on the base 241*; of the upright 2% and this locking pin projects thru the base and engages one of a series of holes 27, 27 provided in the shoe. The holes 27 are arranged concentrically to the pivot stud 25 and the engagement of the locking pin 26 with the holes 27 makes it possible to lock the upright into any angular position which is found necessary because of the angular position of the grading blade with relation to the forms 17 and 18. The upright 24 has a vertical slot 28 extending a predetermined distance from the bottom to the top thereof and thru this slot and a hole in the arms 13 and 14 and the adj usting block 29 passes the bolt 30. Both the face of the adjusting block 29 and that of the upright 24 which face each other are serrated so that when the bolt 30 is tightened by means of the threaded handle 31, the two serrated faces are brought in engagement with each other and firmly clamp the adjusting block 29 in the desired position on the upright 24. In this way the arms 13 and 14 may be supported any predetermined distance above the forms or rails 17 and 18 so that the grader blade 6 in turn is suspended to project a predetermined depth into the road bed between the forms and into the surface of the road bed which is to be graded on the movement of the blade.

To subgrade the road bed the blade of the grading apparatus is placed transversely of the frame thereof between the rails 17 and 18 with the supporting and guiding shoes male ing rolling contact with the top of the forms or r he The blade is preferably placed in a vertical position and is adjusted to be supported in this position by the supporting and guiding shoes so that the bottom edge of the blade is properly gauged and lined up to produce the desired grade of the surface of the road bed when moved between the forms or rails. When the blade is thus located between the rails not only the weight of the blade but a considerable part of the weight of the whole grading apparatus forces the edge of the blade in engagement with the surface of the road bed and this insures that the blade will be held in its properly adjusted position thruout its movement in the road bed and produce a perfect subgrade at a uni form depth the full length thereof.

The pivotal mounting of the uprights 24 on the supporting shoes permits an angular adj ustment thereof with relation to the grading blade 6 whic i is necessary when the blade is moved between the forms or rails at an angle thereto.

The blade 6 is adjustably supported on the uprights 24 of the supporting and guiding shoes so that the subgrading of the surface of the road bed may be done in more than one operation; that is, the blade may first be mounted on the supporting shoes so that but a portion of the grading is done by the grading blade the first time it is moved over the surface of the road bet. In this way the blade may be moved over the surface several times each time grading the surface a little deeper until the desired depth for the surface of the road bed is reached. This of course depends on the depth to which the road bed must be subgraded and on the hardness of the ground of the road bed.

In order to prevent large stones in the road bed from interfering with the grading operation of the grader blade, :1 raking attachment is used in combination with the grader blade and is secured to the grading apparatus ahead of the grading blade.

his raking attachment comprises a suitable frame 85 which is pivotdly mounted to the frame of the grader so as to permh :1 ru 1 ing and lowering of the free end thereon This free end of the frame carries the rake proper which consists of a series of vertical teeth 36, 36 which are suitably spaced and firmly clamped in place between two parallel cross members 37 and 38.

To the free end of the rake supporting frame 35 is pivoted the link 39 which connects the frame with the swinging arm 40. This arm is rotated by a suitable worm gear operated by the worm 41 which in turn is rotated by the shaft 42 and the hand wheel 43 provided at the end thereof. In this way the rake may be raised and lowered to project a predetermined distance into the surface of the road bed ahead of the grader blade so as to rake out the larger stones out of the road bed before the grader blade is moved over it. This is very essential to the proper operation of the grader blade because any large stone that lodges in front or under the grader blade so that it is carried with it, digs a groove into the otherwise smoothly graded surface.

As illustrated in Figure 2 the grader blade, as well as the rake, is somewhat shorter in length than the width of the road bed between the forms or rails 17 and 18. This permits the operator of the apparatus to closely follow first one and then the other of the forms or rails as he steers the appartus over the surface several times. In order to permitthe shifting of the blade from one side to the other without having the supporting and guiding shoes lose contact with the top of the forms or rails, the guiding and supporting shoes and their rollers are made wider than the rails and overhang them first on one side and then on the other as the blade is shifted from one of the forms to the other.

Concrete roads are laidin two or more sections and after one section is finished the next section is laid along side of it. After one section is laid only one rail is needed to form the boundary line for the parallel section and when this is the case one of the supporting and guiding shoes is supported on this single rail while the other is supported by the edge of the already finished section of the road.

I claim:

1. In combination with a grading apparatus having a grading blade and means for moving said grader blade, of an attachment comprising a pair of guide and supporting shoes each comprising a runner, rollers for supporting said runners, uprights pivotally mounted on said runners and means for adjustably supporting the ends of said grader blade on the uprights of said runners.

2. In combination with a grading apparatus having a grading blade and means for moving said grader blade, of an attachment comprising a pair of guiding and supporting shoes one at each end of said grader blade, each of said shoes comprising a runner having an opening therethru, a roller mounted to rotate in said opening and partially projecting therethru, an upright pivotally mounted on said runner serrations formed on said upright, an adjusting block, serrations formed on said adjusting block and means for clamping the serrations of said adjusting block in engagement with the serrations of said upright and means carried by said adjusting block for supporting one end of said grader blade on said upright.

In testimony whereof I aflix my signature.

ZACHERY T. DARROW. 

